Impulse generator



Sept. 8, 1936- R. c. COUPLAND IMPULSE GENERATOR Filed Oct. 2, 1934 2 Sheets-Sheet 1 lnventur Richard E- EnuPl-and .Atturne Sept. 8, 1936. R. c. COUPLAND IMPULSE GENERATOR Filed Oct. 2, 1934 2 Sheets-Sheet 2 Inventor Richard llEimup Patented Sept. 8. 1936 PATENT OFFICE IIWPULSE GENERATOR Richard C. Coupland, United States Army,

Norfolk,

Application October 2, 1934, Serial No. 746,532

' "10 Claims. (01'. 89-27) 7' (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to an impulse generator employed in a synchronized control system such as is used to control the firing of machine guns between the blades of a rotating propeller of aircraft.

The most pressing requirement in a device of this character is reliability of functioning. With this in mind the purpose of this invention is to provide an impulse generator having a single sear which may be selectively controlled by a mechanical or by an electrical operating mechanism. In order to provide a compact structure the elements of the electrical unit are contained in the housing of the impulse generator.

With the foregoing and other objects in view, the invention resides in the novel arrangement and combination of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

A practical embodiment of the invention is illustrated in the accompanying drawings, wherein:

Fig; 1 is a'view in side elevation of a gun control assembly.

' Fig. 2 is a longitudinal sectional view of the impulse generator showing the sear in, engagement with the cam follower.

Fig. 3 is a similar view with the sear disengaged from the follower.

Fig. 4 is a sectional view on the line 4-4 of Fig. 2.

Fig. 5 is a sectional view on the line 5-5 of Fig. 3.

Fig. 6 is a detail view of the cam.

Fig. 7 is a plan view partly in section showing a modification.

Referring to Fig. 1 the gun control assembly consists of an impulse generator A connected to a trigger motor B by means of an impulse cable and cablehousing C.

The impulse generator unit (Figs. 2 and 3) is arranged to constitute a compact integral part of the airplane engine synchronized thereto during or after assembly and it consists of a housing 5 in which is mounted a driven shaft 6 having a gear I by which it receives its energy from a driving shaft 8 ofthe engine. The shaft 6 is supported by anti-friction bearings 9-9 and carries a cam I0 positioned in the lower portion of the housing 5. The shaft 6 rotates at a speed to give a cam impulse for each blade of the propeller of the airplane engine. When the shaft 6 is driven at the same speed as the propeller the cam will have the same number of lobes as there are blades on the propeller while the number of lobes will be doubled if the shaft is driven at half of the propeller speed.

A cam follower I I arranged parallel to the driven or cam shaft 6 is slidably mounted in the housing 5 and has a foot I2 carrying a roller I3 adapted to engage the cam surface of the cam III.

Threaded on the other end of the follower is a 15 plug I4 in which is secured the impulse cable I5 leading to the trigger motor B. The cable is sheathed in a tube I6 which is secured in a socket I I removably held in place by a nut I8 threaded to the housing 5.

Referring to Fig. 2 the cam follower is normally held immovable in a depressed position by means of a sear plunger I9 mounted in the upper part of the housing 5 and arranged to enter a recess 20 in the cam follower. In order to reduce friction the sear plunger carries a number of rollers 2I-2I and the cam follower carries a. roller 22 projecting into the recess 20. The sear plunger is normally urged towards thecam folsear is also provided and is contained in the housing 5. This unit comprises an armature 21 and commutator 28 carried by the driven shaft 6 and a magnetic field 29 carried by a casing 30 mounted on anti-friction bearings 3I-3I and carrying one of the bearings 9 of the shaft 6. The field 29 is of the permanent magnetic type or as shown of the self-excited type imder excitation at all times so that the time lag required to build up a current flow in the closed circuit will be a minimum.

The casing 30 carries brushes 32-32 wiping the commutator 28 and conductors 33-33 lead from the brushes through posts 3434 to a switch 35 on the stick 26. When the switch is closed it causes an increase in the current flow and a consequent increase in the magnetic pull between the armature and the field. This increase is suflicient to rotate the casing 30 against the action of a coil spring 36 whose ends are respectively attached to the casing 30 and to the housing 5. The rotational displacement of the casing is limited by cooperating stops 31-38 on the casing and housing.

The upper portion of the casing 30 is provided with a cam 39 (Figs. 3-5) adapted to project through an aperture 40 in the housing 5. A pair of spaced rollers 4l4 l are carried in a depending portion 42 of the sear plunger 99 and are disposed in the plane of the cam 39. Upon rotation of the casing 30 by closing the electric circuit. the cam 39 engages the nearest roller and retracts the sear plunger from engagement with the cam follower. The point of the cam comes to rest between the rollers 4i and securely holds the sear plunger in retracted position as shown in Fig. 3. The second roller serves in the nature of a stop to supplement or replace the stop 31. When the electric circuit is opened the coil spring 36 restores the casing 30 to the normal position shown in Figs. 2 and 4 and the sear plunger is urged by its spring 23 into engagement with the cam follower.

The trigger motor unit B, which forms the subject of a separate application includes a spring 43 which is generally common to this type of mechanism as seen by my prior patent No. 1,770,125 of July 8, 1930. This spring acts on a slide 44 which receives the impulse transmitted by the cable l and the spring serves to restore the slide when the cam follower is not acted on by the cam It. When the cam follower is depressed by the cam III the cable retracts the slide '44 and compresses the spring 43.

In the modification shown in Fig. '7 the field casing 45 carries a pinion 46 meshing with a rack 41 on the sear 48.

I claim:

1. In a synchronizing mechanism, an impulse generator including a housing, a driven cam shaft extending into the housing, a cam follower mounted in the housing, a scar plunger engageable with the cam follower to hold it inimovable, a spring normally holding the sear plunger into engagement with the cam follower, an armature on the cam shaft, a casing rotatable about'the axis of the cam shaft, a magnetic field on the casing, an electrical circuit between the armature and casing and including aswitch, a spring for rotating the casing, means for limiting movement of the casing, and a cam on the casing engageable with the sear plunger to disengage-it from the cam follower.

2. In a synchronizing mechanism, an impulse generator including a housing, a driven cam shaft extending into the housing, a cam follower mounted in the housing, a scar plunger engageable with the cam follower to hold it immovable, an armature on the cam shaft, a casing rotatable about the axis of the cam shaft, a magnetic field on the casing, an electrical circuit between the armature and casing and including a switch, a spring for rotating the casing, means for limiting movement of the casing, and means on the casing and engageable with the sear plunger'to reciprocate the same.

3. In a synchronizing mechanism, an impulse generator including a housing, a driven cam shaft extending into the housing, a cam follower mounted in the housing, a scar plunger engageable with the cam follower to hold it immovable, a spring normally holding the sear plunger in engagement with the follower, an electrical unit within the housing including a rotatable field member, a spring for said member, and means on said member engageable with the sear plunger to disengage it from the cam follower.

4. In a synchronizing mechanism, an impulse generator including a housing, a driven cam shaft extending into the housing, a cam follower mounted in the housing, a scar plunger engageable with the cam follower to hold it immovable, an electrical unit within the housing including a rotatable field member, a spring for said member, and means on said member engageable with the sear plunger to disengageit from the cam follower.

5. In a synchronizing mechanism, an impulse generator including a housing, a driven cam shaft extending into the housing, a cam follower mounted in the housing, a scar plunger engageable with the cam follower to hold it immovable, an electrical unit within the housing including a rotatable field member, a spring for said member, and means on said member engageable with the sear plunger to reciprocate the same.

6. In a synchronizing mechanism, a driven cam shaft, a cam follower, a sear engageable with the cam follower to hold it immovable, an electrical unit including an armature driven by the cam shaft and a rotatably mounted field, aspring for counter-rotating the field, and means on said field engageable with the sear to disengage it from the cam follower.

7. In a synchronizing mechanism, a driven cam shaft, a cam follower, a scar engageable with the cam follower to hold it immovable, an electrical unit including an armature driven by the cam shaft and a rotatably mounted field, a spring for counter-rotating the field, and means on said field engageable with the sear to reciprocate the sear.

8. In a synchronizing mechanism the combination with a driven cam shaft, a cam follower, and a sear engageable with thecam follower to hold it immovable, of an electrical unit including a rotatably mounted field, means for counter-rotating the field, and means on said field engageable with the sear to disengage it from the cam follower.

9. In a synchronizing mechanism the combination with a driven cam shaft, a cam follower, and asear engageable with the cam follower to hold it immovable, of an electrical unit including a rotatably mounted field, means for counterrotating the field, and means on said field engageable with the sear to reciprocate the sear.

10. In a synchronizing mechanism, a housing, an impulse generator including a follower mounted in the housing, a scar plunger movable transversely of the housing, and-engageable with the follower to hold it immovable, and an electrical unit within the housing and including a rotatable member coaxial with the generator for disengaging the sear plu: ger from the follower.

RICHARD C. COUPLAND. 

